Surgical by-pass procedures and balloon angioplasty are two techniques currently available for recanalizing arteries. The techniques of balloon angioplasty involve the passage of a fine guide-wire through the narrowed area, and the advancing of a catheter carrying the balloon through the narrowed area, so that the balloon rests in the narrowed area or site of stenosis. The baloon is then inflated.
In recent years much attention has been given to the use of laser energy for angioplasty. It has been demonstrated that laser energy can be effective in removing atherosclerotic plaque deposits and much research is currently being done to establish effective techniques. Clinical application has been seriously limited, especially in the coronary circulation, by the risk of perforation of the artery. To date the catheter is inserted and the laser energy is directed forward (antegrade lasing) so that in a tortuous artery it is difficult precisely to direct the energy against the deposit. Thus a perforation can be induced, which of course could be lethal.
Representative balloon angioplasty devices and methods using antegrade lasing are disclosed in the U.S. Pat. Nos. 4,207,874, 4,512,762, 4,576,177, and European patent application No. 153,647.